In this research project, the objective is the examination of morphological alterations in the nervous system of animals in which experimental epilepsy has been produced in order to understand the causes and effects of epilepsy in man. The animal model, created by alumina cream, has been used because it results in chronic recurrent seizures which are more like epilepsy in man, both clinically and electrically, than are other experimental animal preparations. From the study of changes in this experimental model it is proposed that alterations associated with ictal events will lead to common structural changes associated with epilepsy. Alterations of the ionic microenvironment of individual and groups of cells in normal and epileptic brain may provide a definitive basis for some of the structural changes already seen. By coupling extracellular manipulations with tracer, horseradish peroxidase, the results of events in vivo may be observed. It is proposed to study experimental seizures by several associated methods: 1) study by serial excisions alumina-free epileptic animals for histological changes and definition of foci; 2) create a new animal epileptic model to provide access to greater animal population for research; 3) alter the ionic microenvironment of cells by chronic local manipulation to study associated structural changes; 4) study the subcellular changes in membrane structure of astrocytes and neurons in epileptic foci by freeze-fracture and etching techniques; 5) compare morphological alterations in experimental animals to excised epileptic foci in man.